1. Field of the Invention
A preformed bag feeder applicable to packaging machines, and mainly, although not in a limitative manner, to horizontal packaging machines.
2. Description of the Related Art
Horizontal packaging machines working with preformed bags, sealed by their lateral and lower extremities and provided with an open upper mouth, are currently known in the market. These packaging machines are provided with a transporter that moves the preformed bags horizontally, in the vertical position and intermittently through successive opening, filling, closing and filling stations of the upper extremity of the aforementioned bags.
It is also known that such packaging machines have a feeder for the supply of the preformed bags to the transporter in charge of moving them through the successive stations of the packaging machines.
A feeder known for this type of packaging machines is provided with buckets containing the preformed bags in the horizontal position and piled or superimposed vertically, with first means that pick up the successive bags from the buckets and supply them one by one to fastening clamps located at a point of the trajectory of the transporter, the clamps allowing the pick up of the successive bags, in the vertical position, by said transporter.
The first means may be of different configurations, being constituted in one known case by a retractable arm bearing a rotary shaft provided with suction cups that pick up the bags, one by one and in the horizontal position, from a bucket, and the combined retractable and rotary movement of the arm and the shaft supplies the bags in the vertical position to the aforementioned fastening clamps.
A usual problem in this type of feeders is that the preformed bags piled inside the buckets are not perfectly parallel or in matching positions since slackness between the contour of the preformed bags and the internal walls of the buckets is necessary for the bags not to be stuck in their interior and be extracted in an individualized manner by the first means in charge of transferring them to the fastening clamps.
This slackness allows the preformed bags contained in their interior to move and turn slightly in the lateral direction, and therefore the bags are not found exactly in the same position.
The foregoing determines that the successive preformed bags are supplied to the fastening clamps in positions with different degrees of lateral inclination, height or lateral movement.
Given that these fastening clamps are in charge of supplying the successive bags to the transporter by moving them in that same position through the successive work stations, an important problem arises when the bags supplied by the clamps are initially in a position that is excessively turned towards the lateral direction or moved both horizontally and vertically.
This problem can be of such a magnitude that it can lead to the ruling out of the use of packaging machines with preformed bags. I have invented a bag feeder for such packaging machines which effectively avoids this problem.